In recent years, for power saving, high-efficiency power converters that utilize the switching of semiconductor devices called power semiconductor chips have been used widely in the fields of automobiles, railroads, industrial equipment, and power equipment. Power semiconductor chips release large amounts of heat when electric current is applied and thus need to be cooled. They are used in the form of power modules in which electrically conductive materials, heat dissipating materials, and insulating materials associated with them are installed, and there is a demand for size reduction of such modules.
As structures for achieving the size reduction of power modules, double-side cooled power module structures, which are cooled from both sides of a power semiconductor chip, have been proposed for electric vehicles.
Patent Document 1 discloses a structure in which, for achieving low inductance and low loss, parallelized double-side cooled power modules and capacitors are bonded to positive and negative busbars that are in the form of a laminated layer. Patent Document 2 discloses a structure in which parallelized double-side cooled power modules are arranged in the form of a circle. Patent Document 3 discloses a structure in which power modules and air-cooling fins are arranged around a circle and they are placed next to a side surface of a motor.